I don't have a lot, but I do have games for systems I don't (yet) own. I currently don't have an Intellivision, a 3DO, Atari 5200 or 7800, Philips CD-i, or a working Odyssey2, but I have games for each. I figure I will eventually have these systems, especially the cartridge based ones, but it just hasn't been a priority for me.
I have regularly bought games for newer systems I hadn't acquired yet. I had both Rock Band and Guitar Hero III before I had my Xbox 360. In order to help afford the GameBoy Advance, I sold my GameBoy Color months before (while it still had some value). So when I bought the Zelda Oracle games, I had nothing to play them on.
Alternatively, there have been many systems that I bought new that I took forever to get any games for. I got a PS2 at launch, but I don't think I got a game for it for like a year after that.